Retrofit Summit 2025 is the NLA’s annual event exploring how London can retrofit its existing buildings to meet the city’s net zero ambitions. Taking place this November, the summit will bring together leaders across the built environment to share insight, innovation, and lessons learned from delivering retrofit at scale.

As part of the conversation around the Retrofit Summit 2025, Kieron Taylor, Design Director at AKT II, reflects on London’s evolving built fabric, exploring how adaptive reuse, engineering ingenuity, and new digital tools are redefining what retrofit can achieve.

 

London currently ranks as the second most expensive city in the world to build in (Arcadis report, 2025), a reality made more challenging by a nationwide shortage of construction skills amid political and economic uncertainty. In this climate, the imperative is clear: we must embrace digitisation and adopt leaner, smarter approaches to the design and delivery of projects to meet the city’s demand. Our skyline tells a story of continuity and change, where historic facades stand alongside cutting-edge engineering, each structure reflecting the city’s layered evolution and its response to shifting needs over time 

Yet beneath London’s architectural tapestry, the story of many buildings is rarely straightforward, nor single chapter. Retrofit, refurbish, renovation, adaptive reuse - many ways to describe something that is hardly a new concept. Humans have been repurposing structures for generations, especially one’s own home, but today, with the climate emergency looming large and viability metrics being pushed, retrofit is being reimagined as a lifeline - a practical, sustainable way to unlock much-needed spaces for both living and working, without starting from scratch. 

Whether it is a Victorian house or an existing 1960’s tower, does reuse speak a universal language, or are we translating between sectors? Here in lies the magic of retrofit, it’s part engineering, part archaeology, and part creative alchemy. 

The adaptive reuse of London’s buildings is no small feat. It’s a delicate dance of sustainable design, structural engineering acrobatics, a generous helping of experience, and just a pinch of clairvoyance. From navigating century-old foundations to predicting future climate loads, it’s a job that demands precision, imagination, and lots of investigation.

Where the industry faces a critical skills gap, especially within the engineering disciplines, the right skill set is critical to not only unlock the full value achievable of an existing building, but to push the boundaries of our profession to allow quantifiable growth and development for future generations.
 
Design Teams must balance the juxtaposition of modern requirements with historic elements. New build follows a linear, forward thinking codified processes, retrofits demand retrospection, ‘looking back’ and unpicking earlier design principles that are seldom still applicable.

At AKT we have been ‘reverse engineering’ existing assets to unlock potential for decades, which has seen the scale of involvement grow during that time. By harnessing digital toolsets and our internal archive of historical project data, we are able to operate in a lean and highly efficient manner. In large, complex projects, it is neither workable nor necessary to throw hundreds of people at a problem, smart thinking and strategic use of technology help us bridge the gap in engineering capacity.

From an engineering perspective, we see no ‘difference’ between commercial and residential retrofit - they are both future solutions from current questions. And that question changes over time, the current housing crisis requires more than 80,000 new homes to be built in London each year… as of Q2 2025 the number achieved was less than 4000.

This is one issue that we cannot just ‘build our way out’ of, and maximising the reuse of existing stock and integrating these as part of the supply chain with new developments is the only way to have a chance of getting anywhere near to government targets. New York has been going through a similar challenge and actively converting office buildings to residential use to counteract high vacancy rates - are we making the most of this approach in London as a transition for Grade B space? CBRE findings seem to agree as in their recent report:

“Some lower quality offices that have remained vacant for long periods are being repurposed for other uses. In London, 3.3m sq ft of stock at £2.5bn was sold between 2022 and 2024 for conversion to life sciences, hotels, student accommodation and wider residential assets.”

Flexibility in building design remains essential. As engineers, we've historically benefited from generous loading allowances and the “PPI” (put plenty in) philosophy of old, enabling us to leverage residual capacity through advanced analytical methods and performance-driven design. However, this may not be the case moving forward. Contemporary buildings are being designed with heightened efficiency, driven by sustainability goals and cost constraints. As a result, they are operating closer to their limits. Future adaptations, particularly those requiring significant increases in massing, will be far more challenging to justify compared to what has been achievable in the past

Retrofit may not be the newest kid on the block, but it is certainly the one with the most interesting stories to tell. In a city where every building has a backstory and each turn might be hiding a surprise; the art of adaptive reuse is less about nostalgia and more about necessity. We are not just preserving the past; we are engineering the future.

The reality is, this is not a job for the faint-hearted or the spreadsheet bound individual. It is a cross-sector marathon that demands agility, insight, and a respect for the unknown. As we face mounting pressures from housing shortages to climate imperatives, the retrofit conversation must evolve from niche to a parallel norm - reimagining the entire ecosystem of labour, logistics, and learning, where skills and supply chains blend into a unified force for sustainable urban renewal.

So, the question remains… If London’s building stock is ready to be reimagined, are we prepared to evolve our thinking, upskill our workforce, and rewire our supply chains to meet the moment?

Because with the right mindset and collaboration, what once seemed like constraints can become catalysts, and perhaps, with a little engineering magic, you will find that the solutions have been standing right in front of us all along…